Currently, screening of virions is accomplished through various methods and materials. One method is reverse transcription-polymerase chain reaction (“RT-PCR”) based screening of virions wherein highly specific primers are utilized. Use of highly specific primers, though, has disadvantages. For example, only certain species of virions can be found, and failure to find extreme sequence variants of those species occasionally occurs.
The typical, conventional procedure for viral detection is to reverse transcribe the RNA with an RT primer close in proximity to the sequence to be amplified, followed by PCR amplification with a very specific set of primers and conditions, so that a highly specific amplification of a section of the chosen genome occurs. Alternatively, random primer sequences are used for RT-PCR, but these often have very low amplification efficiencies, and the unused primers can interfere with analysis via DNA array methods.
The first method described above for RT-PCR based screening of virions is predicated on the use of highly specific primers for purposes of amplification. Highly specific primers have the disadvantages of (a) only finding one species of virion and (b) occasionally failing to find extreme sequence variants of those species. The second method, using non-specific RT-PCR amplification with random primers, has neither of these problems, but is impractical for purposes of large and specific amplification.
Numerous materials are used in the screening of virions. FTA™ coated materials developed by Flinders University in Australia have been utilized for the preparation of genetic material. FTA™ materials and techniques yield highly purified genetic material bound to the cellulosic base filter for the duration of amplification reactions and other subsequent applications. FTA™ coated base filter materials include, but are not limited to filter paper, Whatman cellulosic BFC-180, 31-ET, glass microfiber, and any other similar filter materials known to those of skill in the art.
Genetic material can be purified from FTA™-coated material and then eluted from the material using a combination of water and elevated temperatures. The released genetic material is a soluble fragment of variable length that is suitable for any manner of amplification and detection methodologies. The elution of the genetic material is important in applications that would not be possible if the genetic material remained bound to the FTA™ coated material. As previously mentioned, FTA™ coating can be included on or within other filter membrane materials, additionally including, but not limited to, GF/F, GF/B, QMB, Anopore, alumina, GF/M, magnetic impregnated, meltblown polymerics, and surface modified polymerics. These filter membranes can yield superior binding capacity, ease of elution, and extended storage of genetic material.
Currently, there is a great need for the detection of traces of nucleic acids from pathogens, such as HIV or hepatitis, in the blood and other biological samples and for highly-sensitive, but broad-specificity, procedures. Essentially, general methods are required for detecting and typing almost any virion in body fluids, such as by the detection of DNA or RNA.